alt Hacker NewsStrongly agree, it’s has loads of problems, my least favourite being the schema is not checked in the way you might think, there’s not even a checksum to say this message and this version of the schema match. So when there’s old services/clients around and people haven’t versioned their schema’s safely (there was no mechanism for this apart from manually checking in PRs) you can get gibberish back for fields that should contain data. It’s basically just a binary blob with whatever schema the client has overlaid so debugging is an absolute pain. Unless you are Google scale use a text based format like JSON and save yourself a lot of hassle.
Replies
- JSON doesn't have any schema checking either.
- You can encode the protocol buffers as JSON if you want a text based format.
There is an art to having forwards and backwards compatible RPC schemas. It is easy, but it is surprisingly difficult to get people to follow easy rules. The rules are as follows:
1) Never change the type of a field
2) Never change the semantic meaning of a field
3) If you need a different type or semantics, add a new field
You can trivially make breaking changes in a JSON blob too. GRPC has well documented ways to make non-breaking changes. If you're working somewhere where breaking schema changes go in with little fanfare and much debugging then I'm not sure JSON will save you.
The only way to know is to dig through CLs? Write a test.
There's also automated tooling to compare protobuff schemas for breaking changes.